Editing Gas constant (section)

== U.S. Standard Atmosphere ==
The [[U.S. Standard Atmosphere]], 1976 (USSA1976) defines the gas constant ''R''<sup>∗</sup> as<ref>{{cite web |url=http://www.sworld.com.au/steven/space/atmosphere/ |title=Standard Atmospheres |access-date=2007-01-07}}</ref><ref name="USSA1976">
{{cite book
 | last = NOAA, NASA, USAF
 | title = U.S. Standard Atmosphere, 1976
 | publisher = U.S. Government Printing Office, Washington, D.C.
 | date = 1976
 | url = https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770009539_1977009539.pdf
 | id = NOAA-S/T 76-1562
}} Part 1, p. 3, (Linked file is 17 Meg)</ref>
: ''R''<sup>∗</sup> = {{val|8.31432|e=3|u=N⋅m⋅kmol<sup>−1</sup>⋅K<sup>−1</sup>}} = {{val|8.31432||u=J⋅K<sup>−1</sup>⋅mol<sup>−1</sup>}}.

Note the use of the kilomole, with the resulting factor of {{val|1000}} in the constant. The USSA1976 acknowledges that this value is not consistent with the cited values for the Avogadro constant and the Boltzmann constant.<ref name="USSA1976"/> This disparity is not a significant departure from accuracy, and USSA1976 uses this value of ''R''<sup>∗</sup> for all the calculations of the standard atmosphere. When using the [[International Organization for Standardization|ISO]] value of ''R'', the calculated pressure increases by only 0.62&nbsp;[[pascal (unit)|pascal]] at 11&nbsp;kilometres (the equivalent of a difference of only 17.4&nbsp;centimetres or 6.8&nbsp;inches) and 0.292&nbsp;Pa at 20&nbsp;km (the equivalent of a difference of only 33.8&nbsp;cm or 13.2&nbsp;in).

Also note that this was well before the 2019 SI redefinition, through which the constant was given an exact value.